Bonding of showerhead (SH) and electrostatic chucks (ESCs) involves bonding of multiple dissimilar materials, e.g., ceramic and metal. These dissimilar materials have very different coefficients of thermal expansion (CTEs), making it challenging to bond the materials together. Additionally, upon exposure of the SH or ESCs to high stress at low and high temperatures, these parts delaminate.
The bonding material currently used to bond SH and ESCs is polydimethyl siloxane adhesive (PDMS). PDMS is a viscoelastic polymer which belongs to a group of polymeric organosilicon compounds also referred to as silicons. Its linear chemical structure is illustrated in Formula I below,
wherein n represents the number of repeat monomer units. PDMS tends to form a three dimensional porous network by crosslinking the linear polymer chains of formula I. Despite its many advantages such as its compliant nature, PDMS cannot retain its adhesive properties at temperatures greater than 150° C. as it begins to delaminate.
Perfluoro elastomers are fluoro-carbon based polymers comprisingtrong carbon-fluorine bonds and are known for their durability and high resistance to oxygen plasma erosion as well as ability to withstand high temperatures greater than 250° C. These polymers are widely used to make o-rings and gaskets for applications involving high temperatures and corrosive fluids. However, independently perfluoro elastomers are not sufficiently compliant to adhere two dissimilar materials, as used in SH and ESCs applications.
Therefore, there remains a need in the art to prepare a bonding component having the compliant characteristics of PDMS along with the durability and high plasma erosion resistance of perfluoro elastomers at varying temperatures spanning from 120° C. to 300° C.